Relatively recent developments in replacement of lost, malformed or diseased teeth have included oral implantology-- the use of so-called implants to anchor teeth prostheses to the jawbones. Approximately 25 years ago a subperiosteal implant technique was developed. In that technique a metallic "saddle" was devised which fit over the jawbone. The false teeth are anchored to prongs extending from the saddle. The prongs serve as the core of the false tooth. This prong has a head portion of a configuration to insure retention of the false tooth crown.
More recently, the endosteal implant was introduced. These implants are inserted (hammered) or emplaced (in a slot) cut along the ridge crest of the jawbone. These are currently known as the vented or ring-type blade implants, but can also include various pin-types and spiral screw-type implants inserted directly into the jawbone. Typical vented blade type of implants are shown in U.S. Pat. Nos. 3,729,825 and 3,465,441.
As described in those patents, these implants are designed with a tapered implanting blade portion which is adapted to be embedded into the patient's jawbone at the ridge crest. A relatively massive head portion extends upward from the shoulders of the blade and serves as a support upon which the artificial tooth structure is mounted. The head is joined to the shoulder of the body portion by a somewhat thinner neck portion which provides a counterset or shoulder preventing the upward loosening of the artificial tooth structure.
The implants are preferably formed of titanium or Vitallium, but may be of any suitable material that is sterilizable and which does not cause rejection or promote infection of the bone tissue or skin tissue growing into contact therewith.
The primary drawback of the endosteal implant is that its use requires great care and skill by the dentist or oral surgeon. There is the possibility of serious injury to the anatomical structures adjacent the implant area such as sinus cavities, nerves, alveolar canals and adjacent natural tooth structures along or under the ridge crests. The head and neck portion of the implant must project the proper depth from the ridge crest and incised tissue. Improper insertion can result in "overseating" of the implant, that is, driving the blade too deeply into the bone tissue. It is thus possible to perforate a sinus cavity or impinge upon a nerve. If the implant is overseated, it must be withdrawn and a larger one emplaced at a shallower depth.
Another problem is retaining the implant in the proper position for several days during which time bone regeneration takes place to hold the implant sufficiently firmly that cementing of the crown portion of the false teeth can take place. If the implant shifts during this bone ingrowth, the final false teeth prosthesis will not be properly aligned.
Since each tooth is inclined at a somewhat different angle from each other tooth in a full set, and different teeth in different patients are inclined differently, it is important that the head and neck portion be angled properly so that the crown portion of the prosthesis fits properly adjacent to natural teeth and adjacent to the other false teeth. Since the implants are generally made of titanium or Vitallium, they are relatively expensive, costing on the order of $50 to $100 for each implant alone. In addition, the metal is relatively brittle, and improper bending and overstressing can cause the implant to snap at the neck portion between the head and the blade portion during bending, or even subsequently when the crown portion of the prosthesis (false tooth) is mounted thereon, or in place in the patient's mouth.
Likewise, the blade may also be bent in a curve to follow the ridgeline of the jaw before the implant is inserted in the jawbone. Endosteal implants as provided by the manufacturers have planar blades, with one or more heads projecting from the upper shoulder of the blade but lying within the plane of the blade. Depending on where the implant is used in the jaw, the blade may have to be formed into curves of various radii. Likewise, the head may have to be rotated with respect to the plane of the blade. Likewise, the head may be angled in the plane of the blade to one side or the other, or bent outwardly or inwardly from the plane of the blade. All of these angular adjustments depend upon the particular location the implant goes, and the particular configuration of that patient's teeth. Proper fitting is a matter of high skill.
At present, there is no known device which can provide for precise bending required for these surgical implants. Currently, dentists and oral surgeons frequently employ pliers to bend implants. This often results in poorly aligned heads, particularly where adjacent heads on the same blade must be inclined at different angles. In addition, this also leads to breakage of the very expensive implants, or removal and reinsertion of the implants. There is, therefore, a significant need for the implant bender and method of the present invention.